fix(web): extend hover-reveal info affordance to touch devices (#1046)

MessageInfoPopover's trigger button carried the same
happy-message-actions-desktop-only class as the other hover-reveal
actions from 4c76668a, so it never rendered on touch-only viewports
(no hover: hover match). Switch it to the always-visible flex pattern
the sibling copy button already uses, matching desktop's hover-reveal
opacity animation on the parent row.

Also widen the action row's desktop-only-row guard to stay reachable
when a tool-only response (no copyable text) still carries model/
duration metadata from its first tool block, so the info popover isn't
hidden behind an empty row on mobile.

web/src/components/AssistantChat/messages/MessageActions.test.tsx

@@ -67,4 +67,53 @@ describe('MessageActions', () => {
 
         expect(screen.queryByRole('button', { name: 'Message details' })).toBeNull()
     })
+
+    it('keeps the info button reachable on touch devices (no hover-only class)', () => {
+        renderActions({
+            align: 'start',
+            copyText: 'message body',
+            metadata: { durationMs: 1250, model: 'gpt-5.2-codex' }
+        })
+
+        const button = screen.getByRole('button', { name: 'Message details' })
+        expect(button.className.split(' ')).not.toContain('happy-message-actions-desktop-only')
+    })
+
+    it('keeps the action row reachable on touch devices for tool-only messages with metadata', () => {
+        // Tool-only assistant turns (no trailing text) have no copyText, but
+        // can still carry model/duration metadata from the first tool block
+        // in the response group (see assistant-runtime.ts toThreadMessageLike).
+        renderActions({
+            align: 'start',
+            copyText: undefined,
+            metadata: { durationMs: 1250, model: 'gpt-5.2-codex' }
+        })
+
+        const button = screen.getByRole('button', { name: 'Message details' })
+        const row = button.closest('.happy-message-actions')
+        expect(row).not.toBeNull()
+        expect(row!.className.split(' ')).not.toContain('happy-message-actions-desktop-only-row')
+    })
+
+    it('keeps the timestamp reachable on touch devices (no hover-only class)', () => {
+        renderActions({ align: 'start', copyText: 'message body' })
+
+        const time = document.querySelector('time')
+        expect(time).not.toBeNull()
+        const wrapper = time!.parentElement!
+        expect(wrapper.className.split(' ')).not.toContain('happy-message-actions-desktop-only')
+    })
+
+    it('keeps the row reachable on touch devices even with neither copy text nor metadata (timestamp-only row)', () => {
+        // DesktopTimestamp always renders inside the row regardless of
+        // canCopy/hasMetadata, so the row is never actually empty -- hiding
+        // it via the hover-only row class would hide a real timestamp.
+        renderActions({ align: 'end', copyText: undefined, metadata: undefined })
+
+        const time = document.querySelector('time')
+        expect(time).not.toBeNull()
+        const row = time!.closest('.happy-message-actions')
+        expect(row).not.toBeNull()
+        expect(row!.className.split(' ')).not.toContain('happy-message-actions-desktop-only-row')
+    })
 })

web/src/components/AssistantChat/messages/MessageActions.tsx

@@ -22,8 +22,7 @@ export function MessageActions({ align, copyText, metadata }: MessageActionsProp
         <div
             className={cn(
                 'happy-message-actions mt-1 flex h-5 items-center gap-1',
-                align === 'end' ? 'justify-end' : 'justify-start',
-                !canCopy && 'happy-message-actions-desktop-only-row'
+                align === 'end' ? 'justify-end' : 'justify-start'
             )}
         >
             {align === 'end' ? <DesktopTimestamp /> : null}
@@ -46,7 +45,7 @@ export function MessageActions({ align, copyText, metadata }: MessageActionsProp
 
 function DesktopTimestamp() {
     return (
-        <span className="happy-message-actions-desktop-only ml-1 items-center">
+        <span className="inline-flex ml-1 items-center">
             <MessageTimestamp className="text-[10px] leading-none text-[var(--app-hint)]" />
         </span>
     )
@@ -61,7 +60,7 @@ function MessageInfoPopover({ metadata }: { metadata: Omit<MessageMetadataProps,
                     type="button"
                     title={t('message.info')}
                     aria-label={t('message.info')}
-                    className="happy-message-actions-desktop-only h-5 w-5 items-center justify-center rounded text-[var(--app-hint)] transition-colors hover:bg-[var(--app-subtle-bg)] hover:text-[var(--app-fg)]"
+                    className="flex h-5 w-5 items-center justify-center rounded text-[var(--app-hint)] transition-colors hover:bg-[var(--app-subtle-bg)] hover:text-[var(--app-fg)]"
                 >
                     <InfoIcon className="h-3.5 w-3.5" />
                 </button>

web/src/index.css

@@ -433,11 +433,6 @@ body {
     margin-top: max(0px, calc((var(--app-chat-line-height) - var(--app-message-action-size)) / 2));
 }
 
-.happy-message-actions-desktop-only,
-.happy-message-actions-desktop-only-row {
-    display: none;
-}
-
 @media (hover: hover) and (pointer: fine) {
     .happy-message-actions {
         opacity: 0;
@@ -450,14 +445,6 @@ body {
         opacity: 1;
         pointer-events: auto;
     }
-
-    .happy-message-actions-desktop-only {
-        display: inline-flex;
-    }
-
-    .happy-message-actions-desktop-only-row {
-        display: flex;
-    }
 }
 
 .aui-md :where(.contains-task-list) {